Retaining means



1, K. G. KARDE N RETAINING MEANS Filed May 23, 1966 Sheet I of 2 Fig. 2b

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RETAINING MEANS Filed May 23, 1966 Sheet 2 of 2 Fig. 5G

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nited States Patent Q U.S. Cl. 28753 Claims ABSTRACT OF THE DISCLOSURE This invention relates to retaining means for removably retaining a socket element on the outer polygonal end of a drive shaft by releasable engagement of said retaining means with an abutment in said socket element.

One object of the invention is to provide improved retaining means of simplified construction and with a long operable life particularly in connection with the transmission of torque and impacts from rotary impact tools, to a socket element or other device disposed thereon.

Another object of the invention is to affix the retaining means of the device to the tip portion of the polygonal end of the drive shaft of such tools as rotary impact tools in a manner to provide better resistance to fatigue under repeated impacts. With such an arrangement, the retaining means is supported in a portion of the driving shaft having the best resistance to fatigue, and combines simplicity of design with a practical operable life.

The above and further objects of the invention will become obvious from the following description and from the accompanying drawings in which three embodiments of the invention are illustrated by way of example. It should be understood that these embodiments are only illustrative and various further modifications of the invention may be made within the scope of the claims.

In the drawings, FIG. la is a longitudinal sectional view through the drive shaft of an impact wrench with the retaining means according to one embodiment of the invention mounted on the polygonal end thereof and a socket element carried thereby. FIG. 1b is a perspective view of the retaining means in FIG. la. FIG. 2a is a longitudinal sectional view similar to FIG. 1a and illustrating a modified embodiment of the retaining means. FIG. 2b is a perspective view of the retaining means in FIG.

2a. FIG. 3 shows a perspective view of the polygonal end with the retaining means in place. FIG. 4 is an end view of the polygonal end in FIG. 1a with the retaining means removed. FIG. 5a is a longitudinal sectional view similar to FIG. 1a but illustrating a further embodiment of the retaining means. FIG. 5b is a perspective view of the retaining means in FIG. 5a. FIG. 6 is a top view of the polygonal end in FIG. 5a. FIG. 7 finally is an enlarged sectional view on line 77 in FIG. 5a.

In FIG. la the anvil 10 of an impact wrench carries a polygonal, preferably square end 11 on to which a socket element or wrench 12 has been slipped. A radial bore 13 is in the usual manner provided in the socket wrench 12 and the inner wall of bore 13 forms an abutment for a retaining means 14 which is afiixed to the square end portion 11. The retaining means 14 has the shape of an angular double-shanked member consisting of a Spring wire of hairpin shape bent along a transverse axis. The legs 15 of member 14 which form one shank of member 14 are used for fixation purposes and are bent at a substantially right angle to the middle portion 19 of member 14. The legs 15 form an acute angle with one another and are at their outer ends provided with outwardly bent hooks 16 disposed in coplanar relation to the legs 15. The middle portion 19 of member 14 forms the other shank thereof and is terminated by a laterally projecting locking hook 17 intended for releasable cooperation with bore 13 of the socket element 12.

The legs 15 are each inserted in a bore 18 disposed at the tip of the square end 11 in a plane perpendicular to its axis of rotation. The bores 18 form an acute angle with one another which is substantially equal to the angle between the legs 15 and the bores 18 converge towards an axial groove disposed centrally in one of the sides of the square end 11. With the legs 15 compressed the hooks 16 will make their insertion into the bores 18 more easy and the bores 18 will receive the legs 15 and guide them into a position clamped frictionally between opposed portions of the respective bores 18-. The middle portion 19 forming the retaining shank will then extend axially along the groove 20 resiliently depressable thereinto and with the locking hook 17 disposed in the bore 13 in order to keep the socket wrench 12 in place. By depression of the locking hook 17 from the exterior via the bore 13 the socket wrench 12 thus obviously can be removed from square end 11.

The retaining means 21 according to the embodiment in FIGS. 2a, 2b ditfers from the embodiment in FIG. 117 only by the provision of a hump 22 at the outermost portion of the retaining shank 19 instead of the locking hook 17. The hump 22 cooperates lockingly with thebore 13 and by drawing the socket wrench 12 axially outwardly the hump 22 is cammed dOWn into the groove 20 by the inner edge of bore 13 permitting the socket wrench to be freely removed. Both types of retainingmeans 14 and 21 can be used alternately on one and the same square end portion.

If the angle between the legs 15 is made somewhat smaller than the angle between the bores 18, the retaining means 14, 21 will have a tendency to spring radially outwardly with respect to square end 11 along the bores 18. This radial spring action amplifies or may replace the spring action of the retaining shank 19 when said shank is pushed down into the grooves 20 by socket wrench 12.

In the embodiment according to FIGS. 5-7 the retaining means 25 is an angle member or leaf spring consisting of a resilient sheet metal strip. The retaining shank 26 thereof has as before a hump 22 thereon or may as an alternative be provided with a locking hook, not shown, for coaction with the bore 13. The fixed shank 27 is slightly curved and clamped frictionally between opposed surfaces in a dovetail groove'28 provided in the end face of the square end portion 11.

As an alternative the fixed shank 27 may be inserted into a cross bore, not shown, provided at the tip of square end 11 transversely to the axial groove 20. Against the inner wall of such a bore the curved shank 27 can take a frictional hold so that the retaining means 25 is retained in the groove 20.

The bore 13 may be omitted in which case the retaining means 14, 21 or 25 will keep the socket Wrench 12 only by frictional engagement between the retaining shank 19, 26 and the inner surface of the socket wrench 12. Also details connected by a cylindrical end can be retained in axially fixed position by the present retaining means in which case the retaining shank will be adapted to coact with an inner peripheral groove in the one of the details having the cylindrical socket provided therein.

What I claim is:

1. Retaining means for removably retaining a socket element on the outer polygonal end of a drive shaft by releasable engagement of said retaining means with an abutment comprising a radial bore disposed in said socket element said socket element being complementary to the end driving portion of said drive shaft, said abutmentforming bore being so positioned in said socket as to coact with one end portion of said retaining means, said retaining means comprising in combination therewith a resilient member of angular double-shanked shape, and a pair of substantially mutually perpendicular intersecting grooves disposed in said polygonal end, each groove receiving one shank portion of said double-shanked member, one of said grooves being substantially perpendicular to said polygonal end and having opposed guiding surfaces at the tip of said end, said surfaces being disposed transversely to the axis of rotation thereof for receiving by resilient deformation and frictionally holding one shank of said member between said surfaces, the other groove extending axially rearwardly along a lateral face of said polygonal end for freely receiving by resilient deformation the other end of said double-shanked member which springs into releasable engagement with said abutment bore.

2. Retaining means according to claim 1 in which said transverse groove is a dovetail groove and said guiding surfaces are opposed surfaces of said dovetail groove extending substantially across and in the end face of said polygonal end.

3. Retaining means for removably retaining a socket element on the outer polygonal end of a drive shaft by releasable engagement of said retaining means with an abutment in said socket element, said retaining means comprising in combination therewith a resilient wire member of hairpin shape bent at its middle portion substantially at right angles about an axis transverse thereto, a pair of spaced bores disposed in a plane perpendicular to the axis of rotation of said polygonal end and at the tip thereof, each of said bores receiving one of the hairpin legs of said member for keeping said member clamped frictionally between said bores, and the portion of said member opposite to said legs extending freely along said polygonal end rearwardly for springing into releasable engagement with said abutment at the rear end portion of said member.

4. Retaining means according to claim 3 in which said bores converge under an acute angle towards an axial groove in said polygonal end, said freely extending portion being disposed in said groove.

5. Retaining means for removably retaining a socket element on the outer polygonal end of a drive shaft by releasable engagement of said retaining means with an abutment comprising a radial bore disposed in said socket element, said retaining means comprising in combination therewith an angularly bent double-shanked leaf spring, and a pair of substantially mutually perpendicular intersecting grooves disposed in said polygonal end, each groove receiving one shank portion of said doubleshanked leaf spring, one of said grooves being substantially perpendicular to said polygonal end and having opposed dovetail surfaces at the tip of said end, said surfaces being disposed transversely to the axis of rotation thereof for receiving by resilient deformation and frictionally holding one shank of said leaf spring between said surfaces, the other groove extending axially rearwardly along a lateral face of said polygonal end for freely receiving by resilient deformation the other end of said double-shanked leaf spring which springs into releasable engagement with said abutment bore.

References Cited CARL W. TOMLlN, Primary Examiner.

W. L. SHEDD, Assistant Examiner.

US. Cl. X.R. 

